The rare sight Friday of armoured vehicles in the capital's streets comes after rights groups said hundreds of security forces had been mobilised in the city.

Local press on Friday published pictures of several vehicles topped with heavy weapons apparently rolling into the capital's suburbs.

"The deployment is not meant to intimidate the people... it is a proactive measure to prevent any bad situation from happening," military police spokesman Kheng Tito told AFP, declining to confirm the numbers of troops mobilised.

He said the move was to "maintain security and public order" and the armed forces would remain in the city until a new government is formed, ending a political deadlock which has gripped the nation following last month's controversial election.

Strongman premier Hun Sen's long-ruling Cambodian People's Party (CPP) claimed it had won that poll -- one of the most fiercely contested votes seen in the country.

But the opposition Cambodia National Rescue Party (CNRP) said it was the real winner, rejecting the CPP's results on the grounds of widespread voting irregularities.

Opposition leader Sam Rainsy has repeatedly vowed to call for nationwide protests unless an independent probe with United Nations participation is opened.

"We do not ban peaceful demonstrations, but if the protests turn violent the forces will take action," added Kheng Tito.

The CNRP has also threatened to boycott parliament, something Hun Sen has said would not prevent him forming a government.

CNRP spokeman Yim Sovann denounced the deployment of the soldiers as a threat.

"It is intimidation against the people, a threat against freedom of speech and demonstration," he told AFP.

Rights group Amnesty International said hundreds of security forces had been moved into Phnom Penh on Thursday, and called on Cambodian authorities and political leaders to ensure a "tense and unpredictable" post-election situation does not slip into violence.

"The Cambodian security forces, which have a chequered record when policing demonstrations, must refrain from using excessive or unnecessary force against demonstrators," Isabelle Arradon, the group's deputy director for the Asia-Pacific, said in the statement.

Cambodia's opposition party earlier this week called on the UN to help resolve the dispute to protect "the victory" of the people.

Hun Sen -- who has been in power for 28 years -- has vowed to establish a government under his leadership despite the opposition's allegations.

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